In the anime everything was covered except for his left face
I think you're are understating Mihawk a bit, his casual swings injure the toughest opponents.
I don't get how Jozu can't cover his body in diamond, it's like luffy not being able to cover himself in rubber.
Exactly, that's what I'm saying... lol. You're arguing that his whole body was covered in diamond.
How am I understating Mihawk, lol? xD Yes, but it's diamond. Again, it's really casual.
Yeah, so? Luffy's body is made out of rubber, it's different scenario to Jozu. Think about it, if Jozu can cover his entire body with diamond, you do realize that he can defeat most swordsmen (Vista, Shiliew, Cavendish, Zoro, Momonga, etc.) with little to no diff. and most brawlers (Luffy, Smoker, Vergo, etc.) can't even hurt him that much, right? We've never seen his entire body covered in diamond and it would be too OP if he did.